Many telephone handsets are equipped with a device termed an HAC coil, or Hearing Aid Compatible coil. The HAC coil acts as an antenna, and broadcasts the audio signal received by the handset to a nearby hearing aid, which contains a similar coil, called a T-coil, which acts as a receiving antenna. This arrangement allows the hearing aid to receive substantially the same audio signal received by the loudspeaker within the handset.
Size restrictions and functional limitations prevent current telephone-hearing aid couplers from providing the quality audio sound required/desired by the hearing impaired. Many devices require the user to switch between operating modes, depending on whether a telephone is being used. Some systems are bulky and cumbersome to use, and most cannot be used with in-the ear and in-the-canal (“ITC”) type hearing aids. Additionally, many prior art devices operate in a set, and very limited frequency range, effectively eliminating the ability of a hearing impaired person to hear sounds across a broad range of frequencies.
Typically, most if not all prior art devices focus on transmitting a signal between a handset of a telephone and a hearing device worn by a user. Signal quality enhancement is dependent on both a transmitting transducer and a receiving transducer. Modifying or enhancing a transmitted signal alone, whether to a hearing impaired person or a person of normal hearing, is not considered. Also, a full compliment of signal modification techniques (e.g. filtering, frequency shifting, phase shifting, etc.) are not employed.
Hence, there is a need for a system and method for modifying an audio signal perceived by a listener that overcomes one or more of the drawbacks identified above.